1. Field of the Invention
The present invention relates to an electronic device, and particularly relates to an electronic device capable of reducing the difference of radiation characteristics of an antenna element in cases where the device is used in portrait orientation and in landscape orientation.
2. Description of the Related Art
A wireless communication function is generally mounted on communication devices such as a personal computer, a cellular phone device, a PDA (Personal Digital Assistant). In recent years, the wireless communication function is also mounted on consumer electronic devices other than communication devices, for example, an audio device, a video device, a camera device, a printer, an entertainment robot, a digital photo frame and so on.
As a wireless communication system, for example, there exists a narrowband wireless communication system using a 5.2 GHz band carrier wave which is proposed in IEEE (Institute of Electrical and Electronic Engineers) 802.11a. There are also a wireless LAN (Local Area Network) system, a near-field wireless communication system which is called as Bluetooth (Trademark) using 2.4 GHz band carrier wave which is proposed in IEEE 802.11b, IEEE802.11 using a MIMO (Multiple Input Multiple Output) system for obtaining a high transmission rate and the like.
In electronic devices larger than a cellular phone device such as a notebook personal computer in electronic devices having the wireless communication function, an antenna element for wireless communication is commonly installed at a corner of a casing (for example, refer to JP-T-2007-503149, JP-A-2006-20136 and Japanese Patent No. 4047283 (Patent Documents 1 to 3)). This is because, when the antenna element is installed at the corner, interference with respect to peripheral components inside the electronic device is reduced and a portion secured for free space is increased, as a result, gain improvement can be expected.
In electronic devices having the wireless communication function, there exists an electronic device which can be used both in portrait orientation and in landscape orientation such as a digital photo frame, in which display is performed so as to be viewed by a user in a normal position when the device is set in portrait orientation as well as in landscape orientation.
In such electronic device, it is necessary that a large difference does not occur in radiation characteristics of the antenna element when used in respective orientations.